1. Field of the Invention
The present invention relates to process and apparatus for the preparation of pure silane by reacting chlorosilanes with lithium hydride.
2. Description of the Prior Art
It is known to this art to react chlorosilanes with lithium hydride to prepare silane. Compare, for example, U.S. Pat. Nos. 3,078,218 and 3,163,590.
The subject chemical reaction may thus be represented as: ##STR1## Insofar as the chlorosilane starting materials are concerned, preferably HSiCl.sub.3 and/or SiCl.sub.4 are used, which correspond to x=1 and 0. The reaction takes place in a medium of molten salts at a temperature on the order of 400.degree. to 500.degree. C.
The processes described in the aforenoted domestic patents, however, do not permit of the preparation of a sufficiently pure silane, and, furthermore, the by-product salts contain appreciable amounts of lithium hydride which prevents their ultimate recycling without first being subjected to appropriate preliminary treatment.